尾悬吊大鼠牙体、牙髓、牙周组织的变化

目的 探讨模拟失重务件下钙、磷的代谢变化及转化生长因子β1(TGF-β1)、c-fos及Ⅰ、Ⅳ型胶原蛋白在牙髓、牙周组织中的功能效应。方法 采用扫描电镜及能谱分析系统对模拟失重组、失重对抗组、正常对照组大鼠牙体、牙髓、牙周组织的Ca、P相对百分含量进行检测，同时用免疫组织化学方法对3组大鼠牙髓、牙周组织中的TGF-β1、c-fos及Ⅰ、Ⅳ型胶原蛋白的表达特征进行观察。结果 模拟失重大鼠的牙体组织Ca的相对百分含量明显下降，P稍升高；牙槽骨Ca、P的含量无显著差异。牙髓组织中TGF-β1、c-fos和胶原Ⅰ的表达均减少，胶原Ⅳ在毛细血管内的表达量增多；牙周组织中它们的含量变化不大。采用人工对抗措施后可部分恢复它们的表达量。结论 失重可能引起牙本质矿化不良，1．5G对抗措施可改善其对牙体组织矿物质代谢带来的不利影响。TGF-β1、c-fos、胶原Ⅰ分泌减少是导致矿化不良的一个重要原因。

Changes of Dentin, Dental Pulp and Periodontium Tissue in Tail-suspended Rats

Objective: To investigate the metabolic changes of calcium and phosphorus in dentin, dental pulp and periodontium in tail-suspended rats, and the functions of TGF-beta 1, c-fos, collagen-I and collagen IV in dentin, dental pulp and periodontium. Method: Relative percentage contents of Ca, P in dentin, dental pulp and periodontium were measured with scanning electron microscope and energy spectrum analytical system in 3 groups of rats. The expression of TGF-beta 1, c-fos, collagen-I and collagen IV were also observed. Result: In the suspension group, the relative percentage content of Ca declined significantly, while P increased slightly. There were no significant differences of Ca, P in alveolar bone. The expressions of TGF-beta 1, c-fos and collagen-I declined, but the expression of collagen-IV in pulp vessel increased. There were no significant changes of expressions of TGF-beta 1, c-fos, collagen-I and collagen-IV in the vicinity of PDL. After adopting artificial countermeasures, the above expressions restored partly. Conclusion: Weightlessness might cause abnormal mineralization in dentin, and 1.5 G artificial countermeasures could eliminate the above changes of mineral metabolism. The poor mineralization of dentin might be associated with the reduced secretion of TGF-beta 1, c-fos and collagen-I in tail-suspended rats.